Net viruses plummet but Zafi and Netsky hold fast

Viruses and worms in the wild are at the lowest for over a year, according to anti-virus companies' monthly reports.

With variants of the Zafi and Netsky worms the most prevalent the major theme this year is the lack of any new viruses in the top then, but anti-virus experts are warning people to stay on their guard.

"What we see is a lot of old viruses dominating the charts," said Graham Cluley, senior technology consultant at anti-virus firm Sophos. "There were 1,200 new viruses recorded last month but it's the old ones that holding position. It just goes to show that people still aren't updating their anti-virus protection."

Russian anti-virus firm Kaspersky confirmed that "the number of malware detected overall in February in absolute terms was low enough to make this month the quietest for the past twelve months."

In March the anti-virus community is warning that the Sober-K worm, which appeared towards the end of February, is likely to hit the top of the charts.

"Sober has been successful very quickly," said Cluley. "The writer of the Sober worm often manages to get it to spread widely in a very short period. This may be because he uses a zombie network or the social engineering techniques associated with it. Sober-K can appear as a letter from the FBI, or as pictures of Paris Hilton. The problem is because people haven't seen any major virus outbreak they think they are safe to open attachments."

In February SC reported an email traversing the web that claimed to be an FBI email. An attachment with the email hid the Sober-K worm.